Denso BHT-805BW Operator's Manual page 9

In environments where static electricity can build into significant
charges (e.g., if you wipe off the plastic plate with a dry cloth), do not
operate the BHT. Doing so will result in malfunction or machine
failure.
When connecting or disconnecting the direct-connect interface cable
to/from the BHT, do not plug or unplug it at an angle, and do not pull
the cable strongly. Doing so will result in a machine failure.
Do not place magnetic cards or the like near the BHT speaker.
Doing so may result in the loss of magnetic data from cash
cards, credit cards, etc.
Do not place your ear near the speaker when tones are being
emitted. Doing so may result in hearing loss.
If the BHT has been stored in a hot (50°C to 60°C, 122°F to 140°F)
and humid place, allow it to sit at room temperature and humidity for
at least one day before use. Using the BHT with the inside being hot
will result in a scanning or machine failure.
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